Acromegaly Flashcards
What is acromegaly?
Acromegaly is the clinical manifestation of excessive growth hormone (GH). Growth hormone is produced by the anterior pituitary gland. The most common cause is unregulated growth hormone secretion by a pituitary adenoma
How does it present?
Space Occupying Lesion
Headaches
Visual field defect (“bitemporal hemianopia”)
Overgrowth of tissues
Prominent forehead and brow (“frontal bossing”)
Large nose
Large tongue (“macroglossia”)
Large hands and feet
Large protruding jaw (”prognathism”)
Arthritis from imbalanced growth of joints
GH can cause organ dysfunction
Hypertrophic heart
Hypertension
Type 2 diabetes
Colorectal cancer
Symptoms suggesting active raised growth hormone
Development of new skin tags
Profuse sweating
Investigations?
Insulin-like Growth Factor 1 (IGF-1) is the initial screening test (raised)
Oral glucose tolerance test whilst measuring growth hormone (high glucose normally suppresses growth hormone)
MRI brain for the pituitary tumour
Refer to ophthalmology for formal visual field testing
Treatment?
Trans-sphenoidal (through the nose and sphenoid bone) surgical removal of the pituitary tumour is the definitive treatment of acromegaly secondary to pituitary adenomas.
Where acromegaly is caused by ectopic hormones from a pancreatic or lung cancer, surgical removal of these cancers is the treatment.
There are medication that can be used to block growth hormone
Pegvisomant (GH antagonist given subcutaneously and daily)
Somatostatin analogues to block GH release (e.g. ocreotide)
Dopamine agonists to block GH release (e.g. bromocriptine)
Somatostatin is known as “growth hormone inhibiting hormone”. It is normally secreted by the brain, gastro-intestinal tract and pancreas in response to complex triggers. One of the functions of somatostatin is to block GH release from the pituitary gland. Dopamine also has an inhibitory effect on GH release, however not as potent as somatostatin.
